From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756321AbcG0Op3 (ORCPT ); Wed, 27 Jul 2016 10:45:29 -0400 Received: from mail-it0-f46.google.com ([209.85.214.46]:37383 "EHLO mail-it0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754377AbcG0Op1 (ORCPT ); Wed, 27 Jul 2016 10:45:27 -0400 Subject: Re: [PATCH BUGFIX V5] block: add missing group association in bio-cloning functions To: Paolo Valente , Tejun Heo References: <1469549700-9732-1-git-send-email-paolo.valente@linaro.org> <1469596932-14448-1-git-send-email-paolo.valente@linaro.org> Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ulf.hansson@linaro.org, linus.walleij@linaro.org, broonie@kernel.org, stable@vger.kernel.org, jmoyer@redhat.com, Nikolay Borisov From: Jens Axboe Message-ID: Date: Wed, 27 Jul 2016 08:45:24 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <1469596932-14448-1-git-send-email-paolo.valente@linaro.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/26/2016 11:22 PM, Paolo Valente wrote: > When a bio is cloned, the newly created bio must be associated with > the same blkcg as the original bio (if BLK_CGROUP is enabled). If > this operation is not performed, then the new bio is not associated > with any group, and the group of the current task is returned when > the group of the bio is requested. > > Depending on the cloning frequency, this may cause a large > percentage of the bios belonging to a given group to be treated > as if belonging to other groups (in most cases as if belonging to > the root group). The expected group isolation may thereby be broken. > > This commit adds the missing association in bio-cloning functions. Added for 4.8, thanks. -- Jens Axboe